Bloggs
I do not believe anyone has advocated use of FLCH
on approach. Descent yes, approach no. In fact, in my recollection, the only person that has even mentioned it in an approach context, is you.
The Boeing 777 FCTM refers to it thus: (my bolding and underlines)
Non-ILS approaches are normally flown using VNAV, V/S, or FPA pitch modes.
The use of FLCH is not recommended after the FAF. Recommended roll modes
are provided in the applicable FCOM procedure.
The cases you cited are not relevant. Both were related to standards / training, rather than “normal ops”.
BTW you still haven’t answered my earlier question about the existence or otherwise of IAS mode in your 717 AFCS.
Cheers. Maui.